English 
Italian Stato dell’arte dei biomarcatori di malattia renale osservato mediante i Programmi di VEQ del Centro di Ricerca Biomedica
The quality of laboratory tests for the Chronic Kidney Disease in Italy through EQA programs
AUTORI
1Centro di Ricerca Biomedica per la Qualità in Medicina di Laboratorio, Azienda Ospedale – Università, Padova
2Dipartimento di Medicina di Laboratorio, Azienda Ospedale – Università, Padova
ABSTRACT
The quality of laboratory tests for the Chronic Kidney Disease in Italy through EQA programs
Introduction: the diagnosis and classification of Chronic Kidney Disease (CKD) are based on laboratory tests. The aim of this paper is to verify their harmonization at national level, through the examination of participants’ results to EQA programs of the Centre of Biomedical Research.
Methods: we considered results of creatinine and eGFR of the last 8 EQA cycles (2013-2020) for a total of 80 lyophilized control samples and results of albumin and albumin/creatinine ratio (ACR) in urine of the last 3 EQA cycles (2018-2020) for a total of 24 lyophilized control materials.
Results: for creatinine measurement, enzymatic assays show the best accuracy, but only 40% of participants use them. For eGFR the 64% of participants use the equation derived by the CKD-Epidemiology Collaboration (CKD-EPI) study and this formula applied to enzymatic creatinine shows the best performances. For urine albumin, analytical variability (median CV%) is lower for all diagnostic systems at pathological concentrations than at concentrations below the cut-off. Important bias still exists between different methods and overall 12% of the albumin results provided by the participating laboratories did not reach the minimum quality level for the clinical use of the measure and for value <30.0 mg/L the number of unacceptable performances increases to 24%. Similar results were found for ACR: overall 14% of the results were unacceptable and for value <3.4 mg/mmol the number of unacceptable performances increases to 21%.
Conclusion: even if some improvements can be observed during the recent years, efforts for a better alignment to international recommendations are needed. A Reference system of higher order is needed to enable standardization of urine albumin measurement results. The participation in specific External Quality Programs is a valuable tool to assess the harmonization of laboratory tests for CKD diagnosis in our country.